title: Nitric oxide promotes survival of cerebral cortex neurons with simultaneous addition of [Fe(II)(β-citryl-L-glutamate)] complex in primary culture.
abstract: It has been reported that the activity of mitochondrial aconitase (m-aconitase) is rapidly inhibited in a variety of cells when exposed to nitric oxide (NO). In present study, we found that NO significantly increased the number of surviving neurons via enhanced mitochondrial functions with simultaneous addition of the [Fe(II)(β-citryl-L-glutamate; β-CG)] complex. In vitro, a variety of aconitase-inhibitors, such as fluorocitrate, cyanide ion, ferricyanide ([Fe(CN)6]), and various oxidants including superoxide anion, inhibited the activity of m-aconitase even in the presence of Fe(II), whereas a NO-donor, nitroprusside (SNP) ([Fe(CN)5NO]), was the only agent that significantly increased activity of that enzyme. Therefore, it is reasonable to assume that NO released from SNP promotes Fe-dependent activation of aconitase. All other tested NO-donors, including 3-morpholino-sydnonimine (SIN), Deta NONOate (NOC18), and NaNO2, also promoted activation of m-aconitase in time- and dose-dependent manners in the presence of Fe(II). The promoting effects of the NO-donors on activation disappeared with the addition of NO-scavengers. In intact mitochondria, all tested NO-donors promoted reactivation of aconitase in a dose-dependent manner in the presence of Fe(II), whereas that was not seen in its absence. These findings suggest that NO released from NO-donors promotes Fe-dependent activation of aconitase. In mixed neuronal and glial cultures, NO-donors except for SNP enhanced mitochondrial activity at low concentrations. Furthermore, simultaneous addition of the [Fe(II)(β-CG)] complex significantly enhanced those activities and greatly increased the number of surviving neurons. Thus, NO can carry Fe ions into m-aconitase via the guide of the tag of β-CG addressed to the enzyme.
authors.affiliation: Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Kobe-Gakuin University, Faculty of Pharmaceutical Sciences, Kobe-Gakuin University; 1–1–3 Minatojima, Chuoku, Kobe 650–8586, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Hamada-Kanazawa
authors.forename: Masanori
authors.initials: M
authors.lastname: Narahara
authors.forename: Masaoki
authors.initials: M
authors.lastname: Takano
authors.forename: Kyong-Son
authors.initials: KS
authors.lastname: Min
authors.forename: Keiichi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Masaharu
authors.initials: M
authors.lastname: Miyake
mesh_terms: D000154:Aconitate Hydratase / Q000378:metabolism*; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects*; D005296:Ferrous Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D061251:Primary Cell Culture; D051381:Rats; D017208:Rats, Wistar
chemical_list: C584236:(beta-citrylglutamate)iron(II); D005296:Ferrous Compounds; D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; D000154:Aconitate Hydratase